Brake drone e46 M3

[gav2612]

Looking for some advice on a droning noise from my 2001 e46 m3 under heavyish braking.
The car otherwise drives great and brakes well with no fade juddering etc. The noise has been there since I bought the car over a year ago, but has become louder over the last few months. I am aware that the M3 cross drilled discs can give a little droning under heavy braking, but this is now getting quite loud!

The noise sounds like its coming from the rear, but not 100%. it is a deep wheel bearing type noise, but only apparent under braking. No noise on loading up either side on cornering, so wouldn't expect a wheel bearing

With the front discs almost at their wear limit and the rears not far behind, I replaced all four corners with oem discs and red stuff pads expecting that would cure the problem. The noise if anything is now worse. Could the red stuff pads have contributed to the problem? Or any other ideas on the noise?

[jas xjr]

Might be a wheel bearing

[Nedz]

Unlikely to be a wheel bearing as the noise would be there all the time usually getting worse the faster you go.I would say its almost certainly just the noise you always get from M3 drilled discs and using a harder pad has probably made it louder.

[martyspain]

Mine does the same thing, and I worried about it when I first heard the noise. However, it seems to be normal, and in regular road use the brakes have held up fine (though they do get very hot).

I wouldn't worry about it too much, but if you want to put your mind at rest, I'd get the brakes checked out by a decent Indy.

[Neil.D]

I considered this quite normal on my M5.

From 75% braking onwards there was a noticable noise. As long as the noise is equal from both sides and the steering is straight I wouldnt worry.

[MattOz]

Think this happens with all drilled disks as it's the trapped air being expanded and then forced out of the holes. Nothing you can do about it and it's not a mechanical issue.

[NickXX]

Mine drones on the track, and pings loudly when you park up. It's normal

[Davidonly]

Yes, mine thrums away under braking once they are hot. Did it with the old and new disks/pads. I was more annoyed to discover some vibration when slowing down moderately quickly from 150mph

Problem solved as if by magic upon my return to the UK and our micky-mouse motorways !

[DMT84]

Mines been doing this for 6 years. I rather like the sound.

[gav2612]

Feel a bit better now, thanks guys. May go back to an oe pad on the rear to see if that makes a difference as the noise is much worse than with the old bmw pads. I now think the majority of the drone seems to be from the rear brakes rather than front. Due an inspection 2 in 2,000 miles, so will also get it looked over then
Gavin